anqermann



(NoModeL) 2 Sheets-Sheet 1.

J. ANGERMANN. THREAD TENSION MECHANISM FOR SEWING MACHINES.

Patented Mar. 4, 18.90.

l/VVEIVTOR WITNESSES:

N. PETERS. Hwro-Uthognphor, Wauhingmn, n. c

2 Sheets-Sheet 2,

(No Model.)

J. ANGERMANN. THREAD TENSION MECHANISM FOR SEWING. MACHINES. No. 422,691.

Patented Mar. 4, 1890'.

INVENTOI? WITNESSES:

ATTORNEYS N. PETERS. Phclr Lilhngnphcn Wanhinglfim 0.64

UNITED STATES PATENT OFFICE.

JULIUS ANGERMANN, OF BERLIN, GERMANY.

THREAD-TEN SlO N MECHANISM FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent No. 422,691, dated March 4, 1890.

Application filed February 9, 1888.

Serial No. 263,514. (No model.)

Patented in England January 14,1888,N0. 619, and in Austria-HungaryApril 13, 1888, No. 9,673 and N0. Z,568.

To aZl whom it may concern:

Be it known that I, J ULIUs ANGERMANN, a

subject of the King of Prussia, residing at new and useful Improvements in Sewing-Machines, (for which I have obtained Letters Patentin England, No. 619, dated January 14, 1888, and in Austria-Hungary, No. 9,673 and No. 2,568, dated April 13, 1888,) of which the following is a specification.

This invention relates to improvements in sewlng-machines, and especially to the devlces for delivering the thread.

The object of my invention is to provide a thread-feedin g attachment of such a construction that when a thicker piece of fabric is under the presser-foota greater quantity of thread will be fed for each stitch than when fftthill piece of fabric is under the presser- In the accompanying drawings, Figure l is a s1de view of a sewing-machine provided with my improvement, the sewing-plate being removed. Fig. 2 is a rear end View of the same, parts being in section. Fig. 3 is a front end view of the same, parts being omitted. Fig. 4 is a vertical sectional view through the headof the supporting-arm. Figs. 5 and G are diagrammatical views showing the different positions of the presser-foot and thread guide. Figs. 7 and 8 are detail views of two thread-guides in different positions.

Similar letters of reference indicate corre sponding parts. The main shafta is provided with the drivlng-pulley a. and an eccentric a from which motion is transmitted by the rod f to the rocking lever g, fixed by a screw to one end of the rocking shaft h in the horizontal arm of the frame A of the sewing-machine. At the head A of the arm A the rocking shaft 72. is provided with a crank g, which by a suitable link g transmits motion to the vert1cally-reciprocating needle-bar 'i in the head A The lever g is provided on its swinging end with a hoolearm 9 provided with an eye through which the thread can be passed. Said rocking lever g is also provided on its top with a screw 9 having a suitable head that can strike against the bottom end of aspringpressed spindle 0' of the disk 0, resting on a disk 0 between which disks the thread passes, said disks forming an automatic tension device.

The presser-bar 7c, to the lower end of which the presser-foot 7.5 is secured, is provided with a transverse pin 75*, on which an eccentric 70 having a handle k is mounted to turn, the rim of the eccentric resting on the part A of the head A. The pin 70 also passes into a vertically-movable spindle 70 in the head A, which spindle 7a is pressed downward by a spring 70. A collar 16 is clamped on the presser-bar it and is provided with an arm 10 from the free end of which a pin 10 passes through a longitudinal slot in an arm k on a I rocking shaft in", mounted in the horizontal arm of the frame A below the shaft h. At that end of the arm on the frame A opposite the one having the head A the shaft in is provided with an arm 76, which is held in position on said shaft by a screw i0 and in its free or swinging end the arm 76 is provided a q, then through the eye 7, and finally through the eye of the needle.

The operation is as follows: When the sewin g-machine is in operation, the rocking arm 9 swings up and down, as does also the hookarm 9 on the same. If the thread is not passed through the eye in the end of the arm 10 the hook-arm will draw a certain quantity of thread from the spool m for each stitch independent of the thickness of the material to be sewed, and if the material is very thick it is evident that the quantity of the thread will not be sufficient and it will break sooner or later. If the thread is passed through the eye 8 inthe end of the arm 70", the quantity of the thread delivered from each stitch will always be in proportion to the thickness of the material. The screw 76 justed that its eye s will be from the eyein the hook-arm g a distance equal to the greatest length of thread required for any one stitch.

If a thick piece of fabric is placed under the presser -foot, it keeps the presserfoot raised, and as the presser-footis raised the arm 10, attached thereto, lifts the free end of the slotted arm 10 by the action. of the stud k and rocks the shaft 70, whereby the swinging" end of the arm is is raised, and as the arm 9 descends and passes said arm k the distance between the eye 8 in the arm 7c" and the eye in the arm .9 .will be equal to the-length of;

thread required for the stitch in the materials, under the presser-foot. (See Figs. 6 and 8.) If the thicker material under the presser-foot, is replaced-by thinner m-aterial, as in.Fig.'5,; the swinging end ofv thearm k descends with"v the presser-foot, and the distance that .thef hook-arm g moves past the. end of the arm 707 will be: decreased, as shown in Fig. 7, 0r,1in; other twords when the arm 70? is raised the; hook-arm g begins to draw thethread 1from the spool sometime before it *has completedf its downstroke-that is, as ;soon:asj it passes the end of thearm k .It is evident that when;

said arm k7. is-raised thehook-armg wiil pass its en dsooner: thanswhen-saidiarm. is 1o,were1d, forwhensaid arim ,klis lowered the'hook-a-rm;

. g onlyi'passes the. end. of said. arm 10 a very;

short time ibefore said ihook-arm has com-f plet-e'd .its. downstrok-e. ;It thus follows: that less :thread will.be.drawn off the spool forg eaclr-stitchwhen thinmaterial .is under the; presser foot than ,will .be -.drawn 01f ,whenf thicker. material is under; the presser-foot,-'for the reason that. asithe thickness of material} increases the distance that theend ofthe arm; g .v moves past. theend of the arm-110 also in-! i creases. At each-upstroke of. therocking le ver g its screw 9 strikes the bottom of the spring-spindle 0 and moves the same upward,

thereby releasing the tension device, so as to permit the thread that has been drawn from 4 frame, twoparallel rock-shafts, two arms attached, respectively, to said shafts adjacent 5 to each other and provided .with thread-eyes which move past each other in the oscillation of the shafts, a presser-bar, an arm attached to said presser-bar, provided-with a.,pin,-aslot- 1, red arm on .one of said. rock-shafts. engaged 6 by said pin for. oscillating-said shaft, and ad- ;j unctive mechanism connected with the drivin g-shaftfor. oscillating the other rock-shaft. 2. -The combination .of 1a sewing-machine .frama; two, parallel rock-shafts, .two; arms at- 6 Itached,-res p eotively, to said shafts adjacent to. each other-and; provided with threadeyes which move past. each other in.the oscillation of the. shafts, .a presserI-bar;adjnnctive. m ech- .anism connecting said ;presser -bar.,w1th.and 7 operating one of saidrocksshafts atension device, and a-stud onthe. arm, of.one of .-said rock-shaftsfor @automatically .releasing. said :tension. device.

In testimony vwhereof .I':hav.e signed .my 7 name. to this specification .ini the presence. of two snbscribingwitn esses.

JULIUS, ANGERMAN-N. Witnesses:

HAnsBorrennn, :HEINRIGHIB'TTGHER. 

